| Parameter |
Value |
| Designation |
C/2023 S2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-10-15T09:03:22.020480Z |
| Orbit solution date (soln_date, UTC) |
2024-06-06T23:12:32Z |
| Obs used |
392 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
25.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-09-28T23:40:21.590400Z |
| Discovery magnitude (MPC) |
15.15 o |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-10-11.0000000 |
| e |
0.99288676 |
| q (au) |
1.067716 |
| a (au) |
150.102592 |
| i (deg) |
20.485436 |
| Ω (om, deg) |
230.562176 |
| ω (w, deg) |
78.109160 |
| M (ma, deg) |
359.997654 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.113 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.113 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
06:10:32.42 |
+11:28:43.2 |
HIP 29168 |
22.90 |
| 2026-07-29 12:00 |
06:10:42.75 |
+11:28:15.1 |
HIP 29168 |
25.37 |
| 2026-07-30 00:00 |
06:10:53.04 |
+11:27:46.8 |
HIP 29168 |
27.85 |
| 2026-07-30 12:00 |
06:11:03.27 |
+11:27:18.2 |
HIP 29168 |
30.34 |
| 2026-07-31 00:00 |
06:11:13.46 |
+11:26:49.4 |
HIP 29168 |
32.82 |
| 2026-07-31 12:00 |
06:11:23.59 |
+11:26:20.4 |
HIP 29321 |
33.88 |
| 2026-08-01 00:00 |
06:11:33.67 |
+11:25:51.1 |
HIP 29321 |
34.88 |
| 2026-08-01 12:00 |
06:11:43.71 |
+11:25:21.6 |
HIP 29321 |
36.02 |
| 2026-08-02 00:00 |
06:11:53.68 |
+11:24:51.8 |
HIP 29519 |
34.76 |
| 2026-08-02 12:00 |
06:12:03.61 |
+11:24:21.8 |
HIP 29519 |
33.15 |
| 2026-08-03 00:00 |
06:12:13.48 |
+11:23:51.6 |
HIP 29519 |
31.66 |
| 2026-08-03 12:00 |
06:12:23.30 |
+11:23:21.1 |
HIP 29519 |
30.30 |
| 2026-08-04 00:00 |
06:12:33.07 |
+11:22:50.4 |
HIP 29519 |
29.09 |
| 2026-08-04 12:00 |
06:12:42.78 |
+11:22:19.4 |
HIP 29519 |
28.03 |
| 2026-08-05 00:00 |
06:12:52.43 |
+11:21:48.2 |
HIP 29519 |
27.15 |
| 2026-08-05 12:00 |
06:13:02.03 |
+11:21:16.8 |
HIP 29519 |
26.46 |
| 2026-08-06 00:00 |
06:13:11.58 |
+11:20:45.2 |
HIP 29519 |
25.98 |
| 2026-08-06 12:00 |
06:13:21.06 |
+11:20:13.3 |
HIP 29519 |
25.70 |
| 2026-08-07 00:00 |
06:13:30.49 |
+11:19:41.2 |
HIP 29519 |
25.63 |
| 2026-08-07 12:00 |
06:13:39.86 |
+11:19:08.9 |
HIP 29519 |
25.78 |
| 2026-08-08 00:00 |
06:13:49.18 |
+11:18:36.3 |
HIP 29519 |
26.13 |
| 2026-08-08 12:00 |
06:13:58.43 |
+11:18:03.6 |
HIP 29661 |
25.34 |
| 2026-08-09 00:00 |
06:14:07.63 |
+11:17:30.6 |
HIP 29661 |
24.64 |
| 2026-08-09 12:00 |
06:14:16.76 |
+11:16:57.4 |
HIP 29661 |
24.16 |
| 2026-08-10 00:00 |
06:14:25.84 |
+11:16:23.9 |
HIP 29661 |
23.90 |
| 2026-08-10 12:00 |
06:14:34.85 |
+11:15:50.3 |
HIP 29661 |
23.87 |
| 2026-08-11 00:00 |
06:14:43.80 |
+11:15:16.4 |
HIP 29661 |
24.05 |
| 2026-08-11 12:00 |
06:14:52.69 |
+11:14:42.3 |
HIP 29661 |
24.45 |
| 2026-08-12 00:00 |
06:15:01.52 |
+11:14:08.0 |
HIP 29661 |
25.05 |
| 2026-08-12 12:00 |
06:15:10.28 |
+11:13:33.6 |
HIP 29661 |
25.83 |
| 2026-08-13 00:00 |
06:15:18.98 |
+11:12:58.8 |
HIP 29661 |
26.78 |
| 2026-08-13 12:00 |
06:15:27.61 |
+11:12:23.9 |
HIP 29661 |
27.86 |
| 2026-08-14 00:00 |
06:15:36.18 |
+11:11:48.8 |
HIP 29661 |
29.07 |
| 2026-08-14 12:00 |
06:15:44.69 |
+11:11:13.5 |
HIP 29661 |
30.39 |
| 2026-08-15 00:00 |
06:15:53.12 |
+11:10:38.0 |
HIP 29661 |
31.79 |
| 2026-08-15 12:00 |
06:16:01.50 |
+11:10:02.3 |
HIP 29661 |
33.27 |
| 2026-08-16 00:00 |
06:16:09.80 |
+11:09:26.4 |
HIP 29661 |
34.81 |
| 2026-08-16 12:00 |
06:16:18.04 |
+11:08:50.3 |
HIP 29661 |
36.40 |
| 2026-08-17 00:00 |
06:16:26.21 |
+11:08:14.0 |
HIP 29994 |
35.18 |
| 2026-08-17 12:00 |
06:16:34.31 |
+11:07:37.5 |
HIP 29994 |
33.23 |
| 2026-08-18 00:00 |
06:16:42.34 |
+11:07:00.9 |
HIP 29994 |
31.32 |
| 2026-08-18 12:00 |
06:16:50.31 |
+11:06:24.0 |
HIP 29994 |
29.44 |
| 2026-08-19 00:00 |
06:16:58.20 |
+11:05:47.0 |
HIP 29994 |
27.60 |